1999 YZ400F Cam question

2 replies to this topic

Posted July 11, 2008 - 11:48 AM


Ok here's the deal, a friend of mine did a complete top end job on another friend of mines 99' YZF400F (new cylinder, piston, rings, valves, springs and cam chain). The bike has no compression since he finished. You can push the kick starter down with your hand! Once we pulled the head and aligned all of the timing marks we see that he a put the cams in 180 degrees off. My question is is there an easy way to spin the cams with out taking everything apart? If so please let me know how, your help would be greatly appreciated!

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  • grayracer513

Posted July 11, 2008 - 12:42 PM


You can not have the cams in 180 degrees off if the timing marks line up. The ignition is triggered off of the crank, and fires every TDC, so there is no right or wrong TDC to pick. If the marks line up. It's timed.

If it has no compression, the first thing to do is to check the valve clearance.

What may be wrong is the flywheel key may be sheared, or pushed out of its keyway during assembly. Probe for the top of the piston through the spark plug hole, and compare where TDC actually is to the marks on the flywheel.

  • 1998YZ400F

Posted July 11, 2008 - 01:50 PM


if you want to spin the cams to correct the timing, assuming its off, just take off the tank and valve cover and the timing chain tensioner. then remove the cap to the cam and you should be able to take out the cam and move it to where its supposed to be. might take a few tries to get it but thats the easiest way.

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